Exhaust treatment system implementing coordinated locomotive control

ABSTRACT

An exhaust treatment system may be associated with a plurality of locomotives in a consist. A plurality of individual controls may each be associated with a separate locomotive, and each of the individual controls may be configured to receive signals indicative of power plant operating parameters and exhaust gas parameters for the associated separate locomotive. A master control may be configured to receive data from the individual controls and supply operating instructions to the locomotives. The master control may also be configured to coordinate initiation and staging of exhaust gas treatment at each of the locomotives in accordance with power settings for each of the locomotives that increase fuel economy and reduce exhaust gas emissions for the entire consist.

TECHNICAL FIELD

The present disclosure relates generally to an exhaust treatment system and, more particularly, to an exhaust treatment system that implements coordinated locomotive control.

BACKGROUND

Power plants, including diesel engines, gasoline engines, natural gas engines, and other engines known in the art, exhaust a complex mixture of air pollutants. The air pollutants may be composed of gaseous and solid material, which include nitrous oxides (NOx) and particulate matter (PM). Due to increased attention on the environment, exhaust emission standards have become more stringent and the amount of NOx and PM emitted from an engine may be regulated depending on the type of engine, size of engine, and/or class of engine. Exhaust aftertreatment systems (ATS) are applied to engines to meet Tier 4 emissions standards. ATS include, but are not limited to, hydro-carbon (HC) dosing systems, diesel oxidation catalysts (DOC), selective catalytic reduction (SCR), diesel particulate filters (DPF), catalytic converters (3-way catalyst), and fuel burners.

A DPF is designed to trap particulate matter and typically consists of a wire mesh or ceramic honeycomb filtration medium. Although efficient at removing particulate matter from an exhaust flow, the use of the particulate filter for extended periods of time may cause the particulate matter to build up in the filtration medium, thereby reducing the functionality of the filter and subsequent engine performance and efficiency. The collected particulate matter may be removed from the filtration medium through a process called regeneration. To initiate regeneration of the filtration medium, the temperature of the particulate matter entrained within the filtration medium must be elevated to a combustion threshold, at which the particulate matter is burned away in the presence of oxygen. This process, called active regeneration, is accomplished by periodically dosing HC in the ATS and raising DOC and DPF temperatures to approximately 600-650 degrees C. Particulate matter may also be passively regenerated at lower temperatures (250-350 degrees C) by Nitrogen Dioxide (NO₂) produced in DOC reacting with soot within the DPF. SCR is designed to reduce NO_(x) emissions. The system works by injecting urea in hot exhaust gas, which undergoes hydrolysis and thermal decomposition, producing ammonia. Ammonia reacts with nitrogen oxides within SCR catalyst to produce nitrogen. Low exhaust gas temperatures make this reaction less efficient, thereby increasing emissions and urea consumption.

If pre-ATS exhaust gas temperatures are lower than 250 degrees C, the power plant needs to undergo thermal management to ensure that pre-ATS exhaust gas temperatures are hot enough to support passive and/or active DPF regeneration and/or urea dosing. This thermal management can be accomplished by controlling engine speeds, engine loads, ignition timing, exhaust gas recirculation (EGR), or using external heating elements such as burners. However, these thermal management techniques generally result in a reduction in fuel economy. Furthermore, the higher the pre-ATS exhaust gas temperatures, the higher is the efficiency of DPF regeneration and/or SCR system which lowers fluid (fuel and/or urea) economy penalty.

One attempt at optimizing the performance of a power plant in a locomotive while regenerating a DPF is described in U.S. Patent Publication No. 2011/0126516 (the '516 publication), by Gallagher et al. published on Jun. 2, 2011. Specifically, the '516 publication describes a method for removing particulate matter from a DPF. The method includes detecting the amount of trapped particulate matter in the DPF, and then creating a trip plan to optimize the performance of a locomotive along a route in accordance with a power setting of a diesel engine at each location along the route. The trip plan allows a controller to determine a region within the trip plan where the power setting of the diesel engine will be greater than a threshold, and increase the temperature of exhaust gases entering the DPF during that region.

Although the exhaust gas treatment system of the '516 publication may improve the performance of a power plant while a DPF is being regenerated, operation of the associated power plant may still be sub-optimal during regeneration. The exhaust treatment system of the '516 publication only considers the loading of particulates within the DPF for one particular power plant, and does not take into consideration many other factors that can affect overall performance, fuel economy and reduction in emissions.

The disclosed exhaust treatment system is directed to overcoming one or more of the problems set forth above.

SUMMARY OF THE INVENTION

In one aspect, the present disclosure is directed to an exhaust treatment system associated with a plurality of individually-controlled locomotives in a group of locomotives. The exhaust treatment system may include a plurality of individual controls, each of the individual controls associated with a separate locomotive in the group of locomotives, and each of the individual controls configured to receive signals indicative of power plant operating parameters and exhaust gas parameters for the associated separate locomotive. The exhaust treatment system may also include a master control configured to receive data from one or more of the individual controls and supply operating instructions to one or more of the separate locomotives in the group of locomotives. The master control may be configured to coordinate initiation and staging of exhaust gas treatment at each of the plurality of individually-controlled locomotives in accordance with power settings for each of the individually-controlled locomotives that increase fuel economy and reduce exhaust gas emissions for the entire group of locomotives.

In another aspect, the present disclosure is directed to a method of performing exhaust treatment for a plurality of individually-controlled locomotives in a group of locomotives. The method may include receiving signals at each of a plurality of individual controls, each of the individual controls being associated with one of the plurality of individually-controlled locomotives, and the signals being indicative of power plant operating parameters and exhaust gas parameters for the associated locomotives. The method may further include receiving data at a master control from one or more of the plurality of individual controls, and supplying operating instructions from the master control to one or more of the individually-controlled locomotives in the group of locomotives, the operating instructions including coordinating initiation and staging of exhaust gas treatment at each of the plurality of individually-controlled locomotives in accordance with power settings for each of the individually-controlled locomotives that increase fuel economy and reduce exhaust gas emissions for the entire group of locomotives.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of a system for controlling multiple locomotives.

FIG. 2 is a flow chart depicting an exemplary disclosed method that may be performed by the system of FIG. 1.

FIG. 3 is another flow chart depicting an exemplary disclosed method that may be performed by the system of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 illustrates a system 100 that may be used for controlling a consist of three locomotives 102, 104, and 106. Although the system is illustrated to include a three-locomotive consist, one of ordinary skill in the art will recognize that the system and method of the disclosure may also be implemented in a two-locomotive consist or in a consist of more than three units such as a four or more locomotive consist. Individual locomotives 102, 104, 106 may also be arranged such that all locomotives are joined directly together in a consist, or some individual locomotives or groups of locomotives may be spaced at different locations along a train with cars connected in between some of the locomotives or groups of locomotives.

First locomotive 102 in FIG. 1 may have a first control 108 configured to control the operation of locomotive 102. Similarly, second locomotive 104 may have a second control 110, and third locomotive 106 may have a third control 112. Each control 108, 110, 112 may include at least an engine control, and a locomotive control, and may additionally include an ATS control if ATS hardware is included on the associated locomotive. A master control 114 may be provided on lead locomotive 102, and may be communicatively coupled to first control 108 through an Automated Consist Management (ACM) processing module 118, to second control 110 through ACM processing module 120, and to third control 112 through ACM processing module 122. Each control 108, 110, 112, 114 and each ACM processing module 118, 120, 122 may include one or more processors, or various combinations of software and hardware, or firmware configured to execute instructions, such as routines, programs, objects, components, or data structures that perform particular tasks or implement particular abstract data types. In various implementations, one or more of ACM processing modules 118, 120, 122 may be separate controls, or alternatively may be software incorporated within an associated control 108, 110, 112. The instructions that are executed by the controls may be coded in different languages, for use with different platforms. The controls may also be practiced with computer system configurations that may include hand-held devices, multiprocessor systems, microprocessor-based or programmable consumer electronics, minicomputers, servers, mainframe computers, and the like. The tasks performed by controls 108, 110, 112, 114, and ACM processing modules 118, 120, 122 may also be performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices. These local and remote computing environments may be contained entirely within the locomotive, or adjacent locomotives in a consist, or off-board in wayside or dispatch centers where wireless communication may be used. This method and system may be applicable to communicating data between any of the linked locomotives 102, 104, 106. The terms “first”, “second”, and “third” locomotive or control are used to identify respective locomotives or controls in the consist and are not meant to characterize an order or position of the vehicles unless otherwise specified. It may be the case that the first and second locomotives are adjacent to and mechanically coupled with one another, or one or more locomotives may be connected together in one or more consists that are spaced apart with non-locomotive cars such as freight cars connected in between the locomotives.

As shown in FIG. 1, controls 108, 110 may be interconnected by a communication link 124, and controls 110, 112 may be interconnected by a communication link 126. Communication links 124, 126 may be any wired or wireless links between controls 108, 110, 112 such as a multi-unit (MU) cable, which is a known method for providing a hard-wired communication link among the locomotives of a consist. For example, if controls 108, 110, 112 include microprocessors, communication links 124, 126 may be part of a network bus such as an Ethernet twisted pair cable linking the microprocessors. Alternatively, each of controls 108, 110, 112 may be associated with a transceiver that transmits and receives wireless signals in communication with each other. Controls 108, 110, 112 may provide operator controls for use by one or more operators to indicate a desired operating condition.

Controls 108, 110, 112 may be configured to control the engines of each locomotive 102, 104, 106, and other operating parameters based on input from a vehicle operator via an input device, as well as input received from various sensors. Information may be received from a plurality of engine sensors and/or ATS sensors, and each control 108, 110, 112 may be configured to send control signals to a plurality of engine actuators and/or ATS actuators. As one example, engine sensors and/or ATS sensors may include exhaust gas sensors located in, or coupled with one or more exhaust manifolds for each of one or more engines provided with each locomotive, exhaust temperature sensors located upstream and/or downstream of various emission control devices, and intake regulated emissions level sensors. Various other sensors such as particulate sensors for a DPF, additional pressure, temperature, flow, air/fuel ratio, and alternate regulated emissions sensors may be coupled to various locations on or in the one or more engines provided with each locomotive 102, 104, 106. As another example, engine actuators and/or ATS actuators may include fuel injectors, HC dosing injectors, reductant injectors used in conjunction with a selective catalytic reduction (SCR) process to reduce NOx levels, and throttle or notch controls. Other actuators, such as a variety of additional valves, may be coupled to various locations in each of one or more engines associated with each of locomotives 102, 104, 106.

Controls 108, 110, 112, and a master control 114 located on a lead locomotive 102 may receive input data from operator input, a remote dispatch center, wayside devices, and/or the various engine, ATS, or locomotive sensors. Master control 114, and controls 108, 110, 112, process the input data, and trigger the engine and/or ATS actuators in response to the processed input data based on instructions or code programmed therein corresponding to one or more routines. Master control 114 may send instructions over a link 116 to Automated Consist Management (ACM) modules 118, 120, 122, which may process those instructions before passing them on to respective controls 108, 110, 112. ACM modules 118, 120, 122 may be configured in particular to process instructions for each individual locomotive control in a consist in such a way that overall results for the entire consist are optimized. In one non-limiting example, ACM modules 118, 120, 122 may be configured to initiate, operate, and stage ATS regeneration in each locomotive of the consist in a manner consistent with increasing fuel economy and/or fluid economy for the entire consist. Fluid economy may include fuel economy and the economy of other fluids such as diesel exhaust fluid (DEF) used during SCR. As one non-limiting example, a determination may be made by one of ACM modules 118, 120, 122 that the associated locomotive has a level of particulate in the DPF that may be less than a level of particulate in another locomotive in the consist. In spite of this determination, initiation of regeneration of that DPF may be initiated before regeneration in the other locomotive because a throttle notch setting for the associated locomotive is temporarily higher for various reasons that may include track grade, operator requirements, load on the locomotive, age of the locomotive, and/or position of the locomotive in the consist. In various implementations, certain ATS functions, such as passive DPF regeneration, DOC, and SCR may be performed at all times or under the majority of circumstances, while other ATS functions such as active DPF regeneration may be controlled in accordance with the present disclosure to be initiated, operated and staged only on a periodic basis.

Controls 108, 110, 112 may be located on locomotives 102, 104, 106, respectively, or one or more of the controls may be remotely located, for example, at a wayside station or a remote dispatch center. The controls may be configured to receive information from a plurality of engine sensors, ATS sensors, and/or locomotive sensors, and may be configured to send control signals to a plurality of engine actuators, ATS actuators, and/or locomotive actuators. Example locomotive sensors may include locomotive position sensors (such as GPS devices 128), environmental condition sensors (which may sense altitude, ambient humidity, temperature, barometric pressure, and/or ambient levels of various pollutants), locomotive coupler force sensors, track grade sensors, locomotive notch sensors (also referred to as throttle sensors), and brake position sensors. Various other sensors may be coupled to various locations in the locomotive. Example locomotive actuators may include a locomotive throttle notch actuator, air brakes, brake air compressor, and traction motors. Other actuators may be coupled to various locations in each locomotive 102, 104, 106.

Master control 114 and controls 108, 110, 112 may be configured to receive inputs from the various engine sensors, ATS sensors, and locomotive sensors, process the data, and trigger the engine actuators, ATS actuators, and locomotive actuators in response to the processed input data based on instructions, look-up tables, one or more maps, or programmed code or algorithms corresponding to one or more routines. For example, master control 114 may be configured to determine a locomotive trip plan including locomotive notch and brake settings, engine operating parameters, and the initiating and staging of exhaust aftertreatment processes based on the locomotive operating conditions and current environmental conditions for each locomotive 102, 104, 106. Each of the controls may be configured to receive engine data and/or ATS data (as determined by the various engine sensors and/or ATS sensors, such as fuel injection sensors, ignition timing sensors, air/fuel ratio sensors, intake NOx sensors, DPF particulate sensors, diesel exhaust fluid (DEF) level sensors, temperature sensors, pressure sensors, and flow rate sensors). The controls may be further configured to process the engine data and/or ATS data, determine engine actuator settings and/or ATS actuator settings, and transfer or download instructions or code for triggering the engine actuators and/or ATS actuators based on routines performed by one or more of master control 114, ACM processing modules 118, 120, 122, and controls 108, 110, 112.

In one example, master control 114 may be configured to determine a trip plan including throttle notch settings for each locomotive 102, 104, 106 based on individual engine operating conditions and operator preferences, and engine injection settings based on the engine operating conditions and the ambient levels of one or more regulated emissions. Individual locomotives and/or one or more consists of locomotives in a train may be operated in accordance with particular notch duty cycles that specify the time spent at each power level or throttle notch level as a fraction of total time of operation. Based on possible differences between the trip plan's time in a notch duty cycle and a reference duty cycle (such as an EPA duty cycle), master control 114 may reconfigure the trip plan. For example, based on the differences, master control 114, alone or in combination with one or more of ACM processing modules 118, 120, 122, and controls 108, 110, 112, may be configured to readjust parameters set during trip planning. These parameters may include throttle notch settings, fuel injection settings, ignition timing, time for initiation of active DPF regeneration, staging of active DPF regeneration for each locomotive 102, 104, 106, time for initiation and/or staging of Selective Catalytic Reduction (SCR) performed by an AFT system, time for initiation and/or staging of HC dosing, and other engine operating parameters and exhaust aftertreatment parameters. In one example, as an actual duty cycle for one or more of locomotives 102, 104, 106 starts deviating from a reference duty cycle, thereby possibly leading to increased exhaust emissions, master control 114, alone or in combination with one or more ACM processing modules 118, 120, 122, may provide instructions to readjust throttle notch settings for one or more locomotives 102, 104, 106 for a trip plan that imposes fuel economy and exhaust emissions as constraints. Master control 114, in conjunction with ACM processing modules 118, 120, 122 may be configured to customize a trip plan, and modify the trip plan during a particular trip for a train based on network data and/or non-network data received from one or more of an operator, remote dispatch center, onboard sensors including engine operating sensors and locomotive sensors, and wayside sensors including hot box detectors, impact detectors, and hot wheel detectors.

Various implementations of this disclosure may include a communication system for communicating data in a locomotive consist. The communication system may include router transceiver units positioned in lead locomotive 102 and each of trail locomotives 104, 106 in the locomotive consist. The router transceiver units may each be electrically coupled to a multi-unit (MU) cable bus in the locomotive consist that interconnects the lead locomotive and the trail locomotives. The MU cable bus may be an existing cable bus that is used in the locomotive consist for transferring non-network control information between the lead and trail locomotives. The router transceiver units may be configured to transmit and/or receive network data over the MU cable bus.

Control information may be transmitted over link 116, which may be a trainline that extends along the train in order to control at least one of tractive effort or braking effort of the train. Data may also be transmitted between different locomotives of the train through communication links 124, 126. Network data and non-network data may be transmitted over communication links 124, 126, and link 116. Link 116 may be an existing trainline such as an electronically controlled pneumatic brake line.

A desired operating condition may be a throttle setting (also referred to as a notch setting) at which the consist should equivalently operate. One of the locomotives, such as first locomotive 102, may be designated a lead unit in which the operator may ride. The operator may provide input to master control 114 in first locomotive 102, along with data received by master control 114 from one or more of controls 108, 110, 112, and other engine and locomotive sensors. Master control 114 may in turn communicate instructions or data to controls 108, 110, 112 over train line 116 and through respective ACM processing modules 118, 120, 122. Operator input may be provided to all of the locomotives in each consist so that an operator may be riding in any one of the locomotives and may provide the operator input via the control of the locomotive in which the operator is riding.

In various alternative implementations, the operator input may include a total horsepower goal, a fuel efficiency goal, an emissions level goal, a power output goal, or a performance goal for each of the locomotives or for the consist as a whole. One or more of master control 114, ACM processing modules 118, 120, 122, and controls 108, 110, 112 may be configured to determine the level of operation of each of locomotives 102, 104, 106. This determination may be made by calculating from an algorithm or by reference to a look-up table, one or more maps, or other data obtained over a network or stored in memory. The operator control may be any input device that can provide information to the linked controls of the consist. For example, the operator control may be a keyboard, a keypad, a joystick or simply a multi-position switch that indicates a notch position. Alternatively, the operator control may be a remote control from a remote control system or remotely located operator.

Control 108 may respond to the desired operating mode as indicated by the operator input and control an operating mode of first locomotive 102. Similarly, second control 110 may respond to the desired operating mode as indicated by the operator input for controlling the operating mode of the second locomotive 104. The third control 112 may also respond to the desired operating mode as indicated by the operator input for controlling an operating mode of the third locomotive 106. The operator input may be any input that is provided to any of the controls 108, 110 or 112. Each of controls 108, 110, 112 may be configured to be set independently from the other controls of each of locomotives 102, 104, 106 of the consist. As one non-limiting example, in at least one mode of operation of the consist as a whole, the operating mode of first locomotive 102 may be different as compared to the operating modes of the other locomotives 104,106. For example, locomotive 102 may be operating at notch 6 whereas locomotive 104 may be operating at notch 5. Additionally or in the alternative, locomotive 102 may be initiating active DPF regeneration as part of exhaust gas aftertreatment, while locomotive 104 may be introducing urea or another reductant into exhaust gases as part of a selective catalytic reduction (SCR) process performed during exhaust gas aftertreatment. Furthermore, the operating mode of the third locomotive may be independent of the other locomotives and may be different than any or all of the other locomotives. In the previously noted example, locomotive 3 may operate at notch 5, 6, or 7, and may not be undergoing any exhaust gas treatment at that time. The coordination of the operation of locomotives 102, 104, 106 may be accomplished by one or more of master control 114, ACM processing modules 118, 120, 122, and controls 108, 110, 112.

Communication links 124, 126 enable communication of current operating information for each locomotive relevant to determination of the desired operating mode for each locomotive 102, 104, 106. As one non-limiting example, at a time when locomotive 104 may be controlled in order to initiate active DPF regeneration because a sensor detects that the level of particulates in a DPF associated with locomotive 104 has exceeded a threshold, communication link 126 may communicate this information to control 112 of locomotive 106. Control 112 may use this information to delay initiation or further staging of DPF regeneration for locomotive 106. Control 112, alone or in combination with master control 114, or any of the other controls, may be configured to prioritize initiation and staging of various emissions control operations for locomotive 106 based on instructions and/or signals received from other controls, sensor inputs, and the current status of various operating parameters for locomotive 106. As one example, a relatively high load on locomotive 106, and high level of particulates in a DPF for one or more power plants on locomotive 106, may result in a determination that initiation and staging of DPF regeneration for locomotive 106 takes a higher priority at that time than fuel economy. In alternative implementations, one or more controls may be configured to determine a need for a higher throttle notch setting for a locomotive based on parameters including, but not limited to, the load being pulled by the locomotive, ambient conditions of temperature and pressure, location of the locomotive, and track conditions. As a result of this determination, the controls may initiate DPF regeneration to take advantage of higher throttle notch settings for that locomotive even though a particulate sensor may indicate that the level of particulates is still below a threshold. ACM processing modules 118, 120, 122 may be interposed between master control 114 and each of controls 108, 110, 112. ACM processing modules 118, 120, 122 may each be microprocessor-controlled devices that intelligently process the operating mode commands from master control 114 and provide the processed data to each of locomotives 102, 104, 106 via link 116. Alternatively, one or more of ACM processing modules 118, 120, 122 may be incorporated as a routine or software in each of corresponding controls 108, 110, 112.

In various implementations, one or more of master control 114, ACM processing modules 118, 120, 122, and controls 108, 110, 112 may be configured to increase overall fuel economy for a consist during ATS regeneration by coordinating the initiation and staging of ATS regeneration amongst the individual locomotives in the consist. The ATS regeneration that is initiated and staged at each locomotive may include active DPF regeneration as discussed above. Additionally or in the alternative, the controls may coordinate the operating schedules of individual locomotives 102, 104, 106 within a consist automatically or via information sent to one or more operators. In one example implementation, a particular locomotive within a consist may require active DPF regeneration as a result of particulates in the DPF for that locomotive having exceeded a threshold amount. One or more of the discussed controls may be configured to alter the throttle notch operating schedules for the particular locomotive and one or more of the other locomotives in the consist or multiple consists in a train. The throttle notch operating schedules for the locomotives in a consist or in multiple consists may be altered in order to increase fuel economy for the ATS regeneration in particular locomotives while simultaneously modifying the throttle notch settings for other locomotives in the consist or multiple consists to provide substantially the same total pulling power for the train as before initiation of ATS regeneration. As one non-limiting example, substantially the same total pulling power may be pulling power for the entire group of locomotives that does not fluctuate by more than plus or minus 10-20%. The controls may be configured to take into consideration factors such as the fuel penalty that may result from initiating DPF regeneration at lower throttle notch settings in view of a demand for more fuel to heat up the exhaust gases in preparation for ATS processes. A consideration of factors such as this fuel penalty may result in the controls being configured to initiate DPF regeneration for a particular locomotive when that locomotive is running at a higher throttle notch setting. Too high of a throttle notch setting may also result in a less than optimal operating point for initiation of DPF regeneration since the high level of exhaust flow already occurring at the higher throttle notch setting may result in a requirement for more energy to heat the exhaust gases to a desired regeneration temperature.

In one example implementation, ACM processing modules 118, 120, 122 may be configured to improve fuel efficiency of the consist. The ACM processing modules may be configured to determine the best notch combination for the consist to obtain the best fuel efficiency, or the best fluid economy—which may include fuel efficiency and economy of liquid urea or other reductant used in SCR. The ACM processing modules may additionally or alternatively be configured to determine the best notch combination for the consist to produce the least amount of emissions. In additional or alternative implementations, the controls may be configured to increase fuel economy by coordinating the initiation and staging of exhaust gas treatment, such as active regeneration of the DPF, for one or more locomotives in a consist. One or more of master control 114, ACM processing modules 118, 120, 122, and controls 108, 110, 112 may be configured to refer to a look-up table, map, or other database in order to determine desired operating modes. As one non-limiting example, control 108 may be configured to refer to an engine fuel map specific to an engine provided with locomotive 102. In this example, engine output power for the engine provided with locomotive 102 may be plotted versus engine speed. In some fuel maps, engine output torque may be plotted versus engine speed. The maximum recommended power for a specific type of use available at any engine speed may be shown by a power limit curve.

Additionally or alternatively, maps may include contours of constant specific fuel consumption for any particular engine. The maps may be based on historical data for the engine, and may be updated based on current data and changing operating parameters. The contours on a map may be expressed as grams of fuel consumed per kW-hr of output energy or liters of fuel consumed per kW-hr of output energy. The specific fuel consumption values of each contour may be expressed as grams of fuel consumed per kW-hr. A map may define a nominal predetermined operating point, and a maximum fuel efficiency operating point may be shown where the output power and engine speed are lower than the nominal operating point. A minimum emissions operating point may also be shown where the output power and engine speed are also lower than the nominal operating point and at a lower power than the maximum fuel efficiency operating point. Operating points on a map may represent combinations of both lower specific fuel consumption and NOx or other pollutant emissions as compared to the nominal operating point. Additional operating points may be examples of increased output power at the same engine speed as the nominal operating point. One or more of these operating points may be selected, for example, by the requirement for a short burst of maximum power for rapid acceleration. The control system on an engine may allow an engine to run at a higher power rating for a limited time, and then automatically reduce the engine to a lower power curve after the specified time period has elapsed.

In some implementations, one or more of master control 114, ACM processing modules 118, 120, 122, or controls 108, 110, 112 may be configured to retrieve instructions from a look-up table, map, or other database that may include one or more operating points providing reduced output power at the same engine speed as a nominal operating point for increasing engine lifetime. The various controls referred to above may be configured to retrieve data that when implemented may result in a combination of slightly increased engine speed and/or reduced operating power (as compared to a nominal operating point) as well as increased engine lifetime due to reduced internal pressures and stresses in the combustion cycle of the engine.

Maps, look-up tables, or other sources of data retrieved from memory and/or over a network may also provide relationships between quantities of various emissions and engine operating parameters. These maps and data may be specific to a particular engine, and may also be continuously or periodically updated based on historical operating data and maintenance information associated with the particular engine. A typical emissions map may include a plot of engine output power versus engine speed. In some emissions maps, engine output torque may be plotted versus engine speed. The maximum recommended power for a specific type of use at any engine speed is shown by a power limit curve. Contours of constant specific NOx emissions or emissions of other compounds may also be shown. The contours may be expressed, for example, as grams of NOx emitted per kW-hr of output energy. A nominal predetermined operating point may be identified on the emissions map. A maximum fuel efficiency operating point, a minimum emissions operating point, a maximum power operating point, and an optimum engine lifetime operating point may also be shown on a map associated with a particular engine. Particular operating points on the emissions map may also represent combinations of both lower specific fuel consumption and emissions compared to the nominal operating point.

Fuel and emissions maps for the engines provided with the locomotives in one or more consists may be used to select desired operating modes for individual locomotives and for groups of locomotives in one or more consists. Data from the individual fuel and emissions maps, or other sources of data, may also be combined to arrive at overall preferred operating characteristics for a train. As one example of the types of tradeoffs that may be made by various implementations of the controls according to the present disclosure, fuel consumption may be found to improve with decreasing engine speed with little change in NOx emissions levels, while NOx emissions may be reduced with a reduction in power but at the expense of increased fuel consumption. Additional tradeoffs may include improvements in fuel consumption realized by maintaining a throttle notch setting for a particular locomotive at low to intermediate settings may be offset by the quantity of fuel needed to bring exhaust gas temperatures to a level required for DPF regeneration. Operating points from the various maps and other sources of historical, current, and implied or extrapolated data, may be selected to minimize particulate and other emissions while also minimizing any effect on fuel consumption.

In alternative systems, the operator input may include a total horsepower requirement, a fuel efficiency level, an emissions output level, a power output requirement or a performance requirement for each of the locomotives or for the consist as a whole. In these implementations, one or more of controls 108, 110, 112, master control 114, or ACM processing modules 118, 120, 122 may calculate by algorithm or determine through a look-up table, map, or other source of data, the level of operation of each of locomotives 102, 104, 106. The operator control may be any input device that can provide information to the linked controls of the consist. For example, the operator control may be a keyboard, a keypad, a joystick or simply a multi-position switch that would indicate a notch position. Alternatively, the operator control may be a remote control from a remote control system or remotely located operator.

Within a locomotive consist, if one or more locomotive power plants require ATS regeneration to remove buildups of particulate matter, master control 114 may be configured to determine the need for filter regeneration, and determine any adjustment to the fluid handling component required to provide sufficient oxygen in the exhaust flow for filter regeneration. The controls may also be configured to determine any effect an adjustment to various parameters for controlling emissions will have on operation of the power source, and determine a correction for the power source to account for the effect. The controls may further be configured to substantially simultaneously implement the adjustment and the correction.

One or more of controls 108, 110, 112, master control 114, or ACM processing modules 118, 120, 122 may embody a single microprocessor or multiple microprocessors that include a means for controlling an operation of exhaust AFT systems and the power plants associated with each locomotive 102, 104, 106. Numerous commercially available microprocessors can be configured to perform the functions of the various controls. Each control may embody a general power source microprocessor capable of controlling numerous engine functions. One or more of the controls may also include a memory, a secondary storage device, a processor, and other components for running an application. Various other circuits may also be associated with one or more of the controls such as power supply circuitry, signal conditioning circuitry, solenoid driver circuitry, and other types of circuitry.

One or more maps relating an exhaust oxygen concentration, a boost pressure, an intake air temperature, an intake air flow rate, an engine fuel injection amount, an injection timing, an injection pressure, an engine power output, an exhaust emission level, and/or a required setting or configuration of a fluid handling component may be stored in the memory of one or more controls 108, 110, 112, 114, or ACM processing modules 118, 120, 122. Each of these maps may be a collection of data in the form of tables, graphs, and/or equations.

One or more of the controls may receive input indicative of a need for particulate filter regeneration, and reference the maps described above to determine an adjustment to a fluid handling component (such as an induction valve, compressor, bypass valve, or recirculation valve included in an exhaust AFT system) required to provide oxygen in the exhaust flow sufficient to facilitate the regeneration event. In order to achieve an appropriate temperature for actively regenerating a DPF, a sufficient supply of oxygen may be needed to properly combust the fuel injected by a burner. Therefore, in response to an indicated need for regeneration, a control may reference the maps to determine an increased opening amount of an induction valve that may allow more air to enter and pass through a power plant to a burner provided in an exhaust AFT, a change in a compressor characteristic that may be provided to increase a pressure and/or a flow rate of air entering and passing through the power plant, an increased opening of a bypass valve that may be provided to amplify an amount of air diverted directly to the exhaust downstream of the power plant, and/or a decreased opening of a recirculation valve such that the concentration of oxygen entering and leaving the power plant may be increased.

The need for active regeneration of a DPF may be based on an elapsed period of time, a pressure or temperature of the exhaust measured or predicted upstream of a DPF, a differential pressure measured or predicted across the DPF, a calculated amount of soot loading, or other similar parameter. One or more of controls 108, 110, 112, master control 114, or ACM processing modules 118, 120, 122 may also be configured to determine a correction to the operation of a power plant for one of locomotives 102, 104, 106 that is necessary to account for the adjustment(s) made to the fluid handling components. In order to continue providing a demanded power output, ensure that operation of the power plants included on locomotives 102, 104, 106 remains within design guidelines, ensure that the emissions remain compliant with government regulations, and ensure that the general performance remains acceptable to an operator thereof, operating characteristics of locomotives 102, 104, 106 may require some correction during a DPF regeneration event. Some of these characteristics may include, among other things, a fueling characteristic (injection amount, pressure, number and/or distribution of injection shots, and injection timing) and an air induction characteristic (boost pressure, and engine valve timing). The controls may be configured to determine what correction may be required to maintain consistent performance or even improve power source operation during the regeneration event (i.e., during the time period when the operational characteristics of exhaust and recirculation circuits are being adjusted to accommodate a regeneration of a DPF). The controls may be further configured to establish and implement various rules and priorities in determining how to coordinate control of all of the individual power plants in a consist of locomotives in order to optimize overall operating parameters for the consist. As an example, master control 114 may be configured to include a rule that schedules ATS regeneration in various individual locomotives in order to increase fuel economy for the entire consist. In another implementation, master control 114 may be configured to coordinate the operating schedules for individual locomotives within a consist to reduce engine out or pre-ATS particulate matter emissions, and thereby lower the frequency and/or duration of ATS regeneration.

Operation of the disclosed system will be described in the following section in connection with FIGS. 2 and 3.

INDUSTRIAL APPLICABILITY

The disclosed exhaust treatment system may be applicable to any system including a plurality of combustion-type devices. Combustion-type devices may include internal combustion engines, furnaces, or any other combustion devices known in the art. Emissions processing such as particulate filter regeneration may affect performance of the combustion devices. The disclosed system may improve overall performance or other operating characteristics of the plurality of combustion devices. In one implementation, the disclosed exhaust treatment system may improve overall fuel economy and/or fluid economy for a locomotive consist during emissions processing such as DPF regeneration. The system may achieve this goal by coordinating the initiation and staging of DPF regeneration and/or other emissions processing in conjunction with other operating parameters amongst the plurality of power plants in locomotives within the locomotive consist.

As shown in FIG. 2, one or more of master control 114, controls 108, 110, 112, and ACM processing modules 118, 120, 122 may receive data from a number of different sources, and process that data in order to coordinate initiation and staging of exhaust gas aftertreatment in one or more locomotives in a consist to achieve preferred operating characteristics for the entire consist. In one possible implementation, at step 202, master control 114 may receive throttle notch data from all locomotives in the consist. The throttle notch data may be communicated to master control 114 through one or more of communication links 124, 126, and 116. At step 204, master control 114 may also receive engine operating data for all locomotives in the consist.

At step 206, master control 114 may receive exhaust aftertreatment data from all locomotives in the consist. This data may include signals from exhaust gas sensors located in, or coupled with one or more exhaust manifolds for each of one or more engines provided with each locomotive, exhaust temperature sensors located upstream and/or downstream of various emission control devices, intake regulated emissions level sensors, particulate sensors for a DPF, additional pressure, temperature, flow, air/fuel ratio, and alternate regulated emissions sensors coupled to various locations on or in the one or more engines provided with each locomotive 102, 104, 106.

At step 208, master control 114 may receive trip plan data for the consist. Trip plan data may be derived from historical data for a particular route that the consist will travel, track grade data, tunnel data, data pertaining to the geographical areas that will be traveled, ambient data, data derived from the same or different consists with similar loads or other operating constraints, data specific to the individual locomotives included in a consist, throttle notch duty cycles required by regulatory agencies, and current operating instructions provided by an operator or dispatch center. The data specific to individual locomotives may include parameters such as throttle notch settings, fuel injection settings, ignition timing, time for initiation of DPF regeneration, staging of DPF regeneration for each locomotive 102, 104, 106, time for initiation and/or staging of selective catalytic reduction performed by an AFT system, time for initiation and/or staging of HC dosing, and other engine operating parameters and exhaust aftertreatment parameters.

The trip plan received by master control 114 in step 208 may optimize the performance of the locomotive consist in accordance with one or more operational criteria for the locomotive consist. Such operational criteria may include the departure time, arrival time, speed limit restrictions along the locomotive consist track, emission rate and mileage rate restrictions along the locomotive consist track, the number, weight and type of rail cars being pulled by the consist, and any other criteria pertinent to the trip. Master control 114 may use an algorithm to compute an optimized trip plan based on parameters involving individual locomotives 102, 104, 106 in the consist, parameters involving the entire train, parameters relevant to the track being traveled, and various objectives of the mission. The algorithm may create a trip plan based on models for train behavior as the train moves along the track as a solution of non-linear differential equations derived from physics with simplifying assumptions that are provided in the algorithm. The algorithm may have access to information from locator elements such as wayside detectors or GPS devices 128, track characterizing elements such as track grade indicators or snow and ice detectors, and additional detectors and sensors that may provide information regarding engine speed, engine load, ambient conditions, ATS operating parameters, and other data relevant to a determination of the trip plan.

At step 210, master control 114 may receive individual locomotive operating data for all locomotives in the consist. Locomotive operating data may include signals indicative of the position of the locomotive (such as received from GPS devices or wayside sensors), signals indicative of environmental conditions (such as altitude, ambient humidity, temperature, barometric pressure, and/or ambient levels of various pollutants), signals from locomotive coupler force sensors, signals from track grade sensors, signals from locomotive notch sensors (also referred to as throttle sensors), and signals from brake position sensors. Various other signals may be received from sensors coupled to various locations in the locomotive.

At step 212, master control 114 may determine which locomotives may require exhaust aftertreatment, such as regeneration of a DPF, HC dosing, or introduction of reductant for SCR. This determination may be based on signals received from fuel injection sensors, ignition timing sensors, air/fuel ratio sensors, intake NOx sensors, DPF particulate sensors, diesel exhaust fluid (DEF) level sensors, temperature sensors, pressure sensors, and flow rate sensors.

At step 214, master control 114, in conjunction with ACM processing modules 118, 120, 122 and controls 108, 110, 112 may coordinate initiation and staging of exhaust gas aftertreatment in one or more locomotives in the consist to achieve preferred operating characteristics for the entire consist. The exhaust gas aftertreatment may include active DPF regeneration, urea dosing for SCR, or other ATS procedures.

FIG. 3 illustrates a method for controlling DPF regeneration in accordance with an implementation of this disclosure. The steps in FIG. 3 may be performed by one or more of master control 114, ACM processing modules 118, 120, 122, and controls 108, 110, 112. As shown at step 302 of FIG. 3, the location of each locomotive in one or more consists may be determined. At step 304, the level of particulate buildup in a DPF for each locomotive may be determined. At step 306, the power demand on each locomotive may be determined.

The data gathered in steps 302, 304, and 306 may be compared at step 308 in order to enable staging of DPF regeneration amongst two or more locomotives of a consist. At step 310, the comparison of data performed at step 308 enables staging of DPF regeneration amongst two or more locomotives of a consist. The staging allows for improvement of the overall fuel economy for the consist. The staging of DPF regeneration amongst two or more locomotives of a consist may also be performed in conjunction with altering throttle notch settings to maintain total power of the consist.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed exhaust treatment system. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed methods. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents. 

What is claimed is:
 1. An exhaust treatment system associated with a plurality of individually-controlled locomotives in a group of locomotives, the system comprising: a plurality of individual controls, each of the individual controls associated with a separate locomotive in the group of locomotives, and each of the individual controls configured to receive signals indicative of power plant operating parameters and exhaust gas parameters for the associated separate locomotive; and a master control configured to receive data from one or more of the individual controls and supply operating instructions to one or more of the separate locomotives in the group of locomotives, the master control being further configured to coordinate initiation and staging of exhaust gas treatment at each of the plurality of individually-controlled locomotives in accordance with power settings for each of the individually-control led locomotives that increase fuel economy and reduce exhaust gas emissions for the entire group of locomotives.
 2. The exhaust treatment system of claim 1, wherein one or more of the master control and the plurality of individual controls is configured to alter the power settings for each of the individually-controlled locomotives automatically based on data received from one or more of a look-up table and a map.
 3. The exhaust treatment system of claim 1, wherein the power settings for each of the individually-controlled locomotives are controlled by an operator.
 4. The exhaust treatment system of claim 1, wherein one or more of the master control and the plurality of individual controls is further configured to coordinate initiation and staging of exhaust gas treatment at each of the plurality of individually-controlled locomotives in accordance with power settings for each of the individually-controlled locomotives that maintain a substantially constant pulling power generated by the group of locomotives.
 5. The exhaust treatment system of claim 1, wherein one or more of the master control and the plurality of individual controls is configured to coordinate initiation and staging of Diesel Particulate Filter (DPF) regeneration at each of the plurality of individually-controlled locomotives.
 6. The exhaust treatment system of claim 5, wherein one or more of the master control and the plurality of individual controls is further configured to control a flow of oxygen into the exhaust gas to facilitate the DPF regeneration in conjunction with the initiation and staging of DPF regeneration at each of the plurality of individually-controlled locomotives.
 7. The exhaust treatment system of claim 6, wherein one or more of the master control and the plurality of individual controls is further configured to control a flow of fuel into the exhaust gas in conjunction with the initiation and staging of DPF regeneration at each of the plurality of individually-controlled locomotives.
 8. The exhaust treatment system of claim 1, wherein one or more of the master control and the plurality of individual controls is further configured to alter the power settings for each of the individually-controlled locomotives in order to increase fluid economy for the group of locomotives.
 9. The exhaust treatment system of claim 8, wherein one or more of the master control and the plurality of individual controls is configured to increase economy of fluid reductant used in exhaust treatment and increase economy of fuel.
 10. A method of performing exhaust treatment for a plurality of individually-controlled locomotives in a group of locomotives, the method comprising: receiving signals at each of a plurality of individual controls, each of the individual controls being associated with one of said plurality of individually-controlled locomotives, and the signals being indicative of power plant operating parameters and exhaust gas parameters for the associated locomotives; receiving data at a master control from one or more of the plurality of individual controls; and supplying operating instructions from the master control to one or more of the individually-controlled locomotives in the group of locomotives, the operating instructions including coordinating initiation and staging of exhaust gas treatment at each of the plurality of individually-controlled locomotives in accordance with power settings for each of the individually-controlled locomotives that increase fuel economy and reduce exhaust gas emissions for the entire group of locomotives.
 11. The method of claim 10, wherein one or more of the master control and the plurality of individual controls is configured to alter the power settings for each of the individually-controlled locomotives automatically based on data received from one or more of a look-up table and a map.
 12. The method of claim 10, wherein the power settings for each of the individually-controlled locomotives are controlled by an operator.
 13. The method of claim 10, wherein one or more of the master control and the plurality of individual controls is further configured to coordinate initiation and staging of exhaust gas treatment at each of the plurality of individually-controlled locomotives in accordance with power settings for each of the individually-controlled locomotives that maintain a substantially constant pulling power generated by the group of locomotives.
 14. The method of claim 10, wherein one or more of the master control and the plurality of individual controls is configured to coordinate initiation and staging of Diesel Particulate Filter (DPF) regeneration at each of the plurality of individually-controlled locomotives.
 15. The method of claim 14, wherein one or more of the master control and the plurality of individual controls is further configured to control a flow of oxygen into the exhaust gas to facilitate DPF regeneration in conjunction with the initiation and staging of DPF regeneration at each of the plurality of individually-controlled locomotives.
 16. The method of claim 15, wherein one or more of the master control and the plurality of individual controls is further configured to control a flow of fuel into the exhaust gas in conjunction with the initiation and staging of DPF regeneration at each of the plurality of individually-controlled locomotives.
 17. The method of claim 10, wherein one or more of the master control and the plurality of individual controls is further configured to alter the power settings for each of the individually-controlled locomotives in order to increase fluid economy for the group of locomotives.
 18. The method of claim 17, wherein one or more of the master control and the plurality of individual controls is configured to increase economy of fluid reductant used in exhaust treatment and increase economy of fuel.
 19. The method of claim 10, wherein the master control supplies operating instructions to one or more of the locomotives based on a corresponding nominal operating point for the one or more locomotives selected from a group of operating points consisting of a fuel efficiency operating point, an emissions operating point, a power operating point, and an engine lifetime operating point.
 20. A locomotive consist control system for controlling a plurality of locomotives in a consist, the control system comprising: a plurality of individual controls, each of the individual controls associated with a separate locomotive in the consist, and each of the individual controls configured to receive signals indicative of power plant operating parameters and exhaust gas parameters for the associated separate locomotive; and a master control configured to receive data from one or more of the plurality of individual controls and supply operating instructions to one or more of the locomotives in the consist, the master control being further configured to coordinate initiation and staging of exhaust gas treatment at each of the plurality of locomotives in accordance with power settings for each of the locomotives that increase fuel economy and reduce exhaust gas emissions for the entire consist, wherein one or more of the master control and the plurality of individual controls is configured to alter the power settings for each of the locomotives automatically based on data received from one or more of a look-up table and a map. 